- [[Newton's Law of Universal Gravitation]] - acceleration of gravity: - About $9.8 m/s^2$ downward (near Earth's surface) - does not depend on mass of object - every object accelerates that much downward on Earth - (weight) force of gravity: - the force of gravity from the Earth acting on an object with mass $m$ is - $F = mg$ - $g$ is the magnitude of gravitational acceleration ($9.8 m/s^2$ as stated above)